212 HOWARD V. KNOX: element of truth. For, so long as our attention is con- fined strictly to our perceptual experience, there is no causation, no orderly succession of events, but mere chaos. On the other hand, our distinction enables us to give a meaning, which is otherwise lacking, to the separation of psychology from the other sciences. We can now say, without self-contradiction, that psychology has for its pro- vince the stream of consciousness, in contradistinction to the physical sciences, which deal with the external world. It will be remembered that Kant says : " We never, even in experience, ascribe the sequence or consequence (of an event or something happening that did not exist before) to the object, and distinguish it from the subjective sequence of our apprehension, except when there is a rule which forces us to observe a certain order of perceptions and no other : nay, ... it is this force which renders the re- presentation of a succession in the object possible". 1 This I would venture to correct as follows : We should not distinguish between the subjective sequence of our appre- hension and the course of events in the external world, were it not that thus alone are we enabled to introduce among our perceptual experiences a coherent order which in them- selves they do not possess. From the manner in which the notion of externality is arrived at, it is clear that it refers primarily not to ' objects,' simply as such, but to physical events. But, in the first place, inasmuch as events in the physical world are known to us as changes in and among, and actions and reactions between, material bodies, it follows that these bodies must, at least so far, be thought of as themselves external. But, further, it is impossible, when once we have admitted the necessity of the notion of externality as regards material events, to avoid allowing it to apply to all material bodies qua material : because (1) a thing can only be understood with reference to its history, and this has to be distinguished from the experiences which in point of time may lead up to our perception of it (see example, p. 207) ; (2) it is im- possible to follow out in imagination the course of material events in dissociation from the relatively permanent parts of the material world ; (3) every material object has to be re- garded as at least the possible subject of changes either internal changes, or changes of position. Strictly speaking, it is pure tautology to say that material things are to be regarded as external : so that the above 1 Max Miiller's Kant's Critique of Pure Reason, vol. ii., p. 172.
